Arthroplasty is the standard of care for the treatment of shoulder joint arthritis. A typical humeral head replacement which attempts to mimic anatomic conditions involves a metallic humeral stem and a modular head replacement, capable of multiple positions for optimal bony coverage. Such humeral head replacement might articulate with the native bone or an opposing glenoid resurfacing device, which may be manufactured from UHMWPE or any other acceptable material. Such humeral stem is usually offered in one or several inclination angles ranging from 125 degrees to 140 degrees.
For more severe cases of shoulder arthritis, the standard treatment is a reverse reconstruction, which includes reversing the kinematics of the shoulder joint. This is performed by securing a semi-spherical device to the glenoid, referred to as a glenoid sphere, and implanting a humeral stem with a modular cavity capable of receiving the glenoid sphere. The humeral stem is usually offered in one fixed inclination angle between 135 degrees and 155 degrees, with 155 degrees being the angle currently preferred by a majority of surgeons.
As patient disease may progress after anatomic treatment, revision surgery may be necessary to perform a reverse reconstruction of the shoulder. Removal of anatomic devices that have integrated into the patient's bony anatomy may prove to be difficult for the surgeon, and could potentially cause excessive patient bone loss.